#include "der_construction.hh"
#include <iostream>

der_construction::der_construction():sum()
{   
    //这里首先是调用基类的构造函数
    //其次才是这里
    std::cout<<"this is empty thing"<<std::endl;
}

der_construction::~der_construction()
{
    std::cout<<"derive deconstrucion"<<
    std::endl;
}

void der_construction::show(double a,double b)
{
    number1=a;
    number2=b;
    std::cout<<" "<<std::endl;
}